Single sensor color video cameras typically utilize a color filter to separate the color components of an image. The pixels or pixel regions on the sensor (for example a CCD or CMOS chip) are read out, or scanned out, to produce video color component signals from the pixels or pixel regions associated with respective colors, for example, green, red, and blue stripe regions or checkerboard regions on the sensor that receive the corresponding filtered light of the image. In this manner, color separation can be achieved.
One type of filter, which has advantages for single sensor operation is a so-called Bayer pattern filter, illustrated in FIG. 1. This filter has a checkerboard type of pattern with green filter regions arranged diagonally as every other square on every line. The red and blue filter regions alternate on the diagonals and are present as every other square on every other line. In another possible arrangement, the green squares are instead white, with green being derived from luminance and the other colors.
As seen in FIG. 1, only half of the total filter regions pass green, only one quarter of the total filter regions pass red, and only one quarter of the total filter regions pass blue. As in other single sensor color systems, there are trade-offs between the need to separate colors, and the desire to also achieve reasonable good resolution in color, notwithstanding the fact that, after filtering, only a fraction of the light of each color is actually incident on the sensor surface.
It is among the objects of the present invention to improve performance of single sensor video cameras by processing to enhance perceived color resolution.